Ghosts and infrasound

Ghosts and
infrasound

Manchester - Mysteriously snuffed out candles, weird sensations
and shivers down the spine may not be due to the presence of ghosts
in haunted houses but to very low frequency sound that is inaudible
to humans.

British scientists have shown in a controlled experiment that
the extreme bass sound known as infrasound produces a range of
bizarre effects in people including anxiety, extreme sorrow and
chills -- supporting popular suggestions of a link between infrasound
and strange sensations.

"Normally you can't hear it," Dr Richard Lord, an acoustic
scientist at the National Physical Laboratory in England who worked
on the project, said on Monday.

Lord and his colleagues, who produced infrasound with a seven
meter (yard) pipe and tested its impact on 750 people at a concert,
said infrasound is also generated by natural phenomena.

"Some scientists have suggested that this level of sound
may be present at some allegedly haunted sites and so cause people
to have odd sensations that they attribute to a ghost -- our findings
support these ideas," said Professor Richard Wiseman, a psychologist
at the University of Hertfordshire in southern England.

In the first controlled experiment of infrasound, Lord and Wiseman
played four contemporary pieces of live music, including some laced
with infrasound, at a London concert hall and asked the audience
to describe their reactions to the music.

The audience did not know which pieces included infrasound but
22 percent reported more unusual experiences when it was present
in the music.

Their unusual experiences included feeling uneasy or sorrowful,
getting chills down the spine or nervous feelings of revulsion
or fear.

"These results suggest that low frequency sound can cause
people to have unusual experiences even though they cannot consciously
detect infrasound," said Wiseman, who presented his findings
to the British Association science conference.

Infrasound is also produced by storms, seasonal winds and weather
patterns and some types of earthquakes. Animals such as elephants
also use infrasound to communicate over long distances or as weapons
to repel foes.

"So much has been said about infrasound -- it's been associated
with just about everything from beam weapons to bad driving. It's
wonderful to be able to examine the evidence," said Sarah
Angliss, a composer and engineer who worked on the project. --
CNN News